國外主(zhu)要以氣(qi)壓(ya)傳(chuan)動(dong)(dong)、氣(qi)流和箱(xiang)體移(yi)動(dong)(dong)等沖擊(ji)方式(shi)為主(zhu)。由于氣(qi)壓(ya)傳(chuan)動(dong)(dong)式(shi)沖擊(ji)試驗箱(xiang)所(suo)(suo)需(xu)配套(tao)設(she)(she)備(bei)多數為標準件(jian),零部件(jian)選擇方便,這種沖擊(ji)方式(shi)試驗設(she)(she)備(bei)被廣泛(fan)采用,技術比(bi)較成熟。此類氣(qi)壓(ya)傳(chuan)動(dong)(dong)式(shi)沖擊(ji)試驗箱(xiang)通過(guo)(guo)(guo)機組的加熱(re)系統(tong)和制冷(leng)(leng)系統(tong),分(fen)別(bie)產生一個(ge)高(gao)(gao)溫(wen)(wen)(wen)環境(+70℃~+ 150℃)和一個(ge)低溫(wen)(wen)(wen)環境(-25℃~-65℃),根(gen)據溫(wen)(wen)(wen)度(du)(du)沖擊(ji)試驗的相(xiang)關要求,將被測(ce)(ce)元件(jian)放入(ru)(ru)指定(ding)溫(wen)(wen)(wen)室(shi)(shi)的載物(wu)籃(lan)內,待兩溫(wen)(wen)(wen)室(shi)(shi)達(da)到預(yu)設(she)(she)溫(wen)(wen)(wen)度(du)(du)且穩(wen)定(ding)時,通過(guo)(guo)(guo)氣(qi)壓(ya)傳(chuan)動(dong)(dong)機構牽動(dong)(dong)載物(wu)籃(lan),實現籃(lan)內被測(ce)(ce)元件(jian)(如:電(dian)子器件(jian))在(zai)高(gao)(gao)低溫(wen)(wen)(wen)室(shi)(shi)間的移(yi)動(dong)(dong)。移(yi)動(dong)(dong)過(guo)(guo)(guo)程中高(gao)(gao)低溫(wen)(wen)(wen)室(shi)(shi)相(xiang)通,被測(ce)(ce)元件(jian)也由高(gao)(gao)溫(wen)(wen)(wen)或低溫(wen)(wen)(wen)狀態進入(ru)(ru)另一溫(wen)(wen)(wen)室(shi)(shi),所(suo)(suo)以會(hui)有大量(liang)冷(leng)(leng)熱(re)負荷帶入(ru)(ru),機組要通過(guo)(guo)(guo)制冷(leng)(leng)系統(tong)或加熱(re)系統(tong)迅(xun)(xun)速恢復(fu)到各溫(wen)(wen)(wen)室(shi)(shi)預(yu)定(ding)溫(wen)(wen)(wen)度(du)(du)。當被測(ce)(ce)元件(jian)所(suo)(suo)在(zai)溫(wen)(wen)(wen)室(shi)(shi)溫(wen)(wen)(wen)度(du)(du)長時間保持穩(wen)定(ding)后(hou),再(zai)經過(guo)(guo)(guo)傳(chuan)動(dong)(dong)機構將載物(wu)籃(lan)反向牽動(dong)(dong),把被測(ce)(ce)元件(jian)帶回(hui)原(yuan)溫(wen)(wen)(wen)室(shi)(shi),同樣須迅(xun)(xun)速恢復(fu)到預(yu)定(ding)溫(wen)(wen)(wen)度(du)(du),當溫(wen)(wen)(wen)度(du)(du)再(zai)次長時間穩(wen)定(ding)后(hou),再(zai)重復(fu)上述操作,完(wan)成多次溫(wen)(wen)(wen)度(du)(du)循環沖擊(ji)試驗。工作原(yuan)理(li)如下圖所(suo)(suo)示。
圖(tu)1-1氣壓傳動(dong)式沖(chong)擊試驗箱工作原(yuan)理(li)圖(tu)
氣流式沖擊試驗箱溫度沖擊原理與氣壓傳動式沖擊試驗箱類似,但其結構設計新穎,靠交換改變進入試驗箱內的冷熱氣流,來實現對元件的冷熱沖擊。元件在箱體內無需移動,運動部件少,機構簡單可靠性高,而且可以承載更多試驗元件,提高了空間利用率和試驗效率。這種沖擊方式出現較晚,機構整體布置和配套設備都要重新設計,與以往的冷熱沖擊試驗箱有較大區別。而此類試驗箱又分為可移動式、不可移動式兩種。